This invention relates in general to a method and apparatus for testing the presence of materials in gases, such as air, and, in particular, to a new and useful testing tube for measuring chromate and chromic acid aerosols in air and to a method of carrying out the testing.
According to the MAK-value list, zinc chromate is a potentially carcinogenic substance. In two other chromates, as well as in chromic acid (CrO.sub.3), a carcinogenic is also suspected. Frequent and regular monitoring of these substances is, therefore, absolutely essential.
A known tester for determining chromic acid aerosols uses a special chemically impregnated filter paper which is arranged in a receiver in front of a suction pump. For carrying out the test, the contents of several ampoules is mixed in a plastic injection syringe and is placed on the filter paper as a reagent. The chromic acid aerosol to be determined in the testing air, pumped through the filter paper by means of the suction pump, then leads to discoloration of the charged reagent drop. A color comparison with a standard then determines the concentration value. This known method is complicated because of the necessary preparations, and it requires particularly sufficient preparation time ("M S A Universal Tester", Bulletin No. 0815-6).